The present invention is directed to coin-telephone auditors, which monitor the money collected by coin telephones so that the information can be obtained remotely.
Operation and maintenance of coin-operated telephones are quite expensive to the telephone operating companies. Among the many factors that contribute to this expense is simply the need to collect the money from the coin telephones. The cost of making collections differs from telephone to telephone since it can depend greatly on the telephone's location, but it has been estimated that the average cost of a single collection is on the order of ten dollars. Thus, any measures that can be taken to reduce the frequency with which the collections must be made can contribute significantly to the profitability of operating the coin telephone.
Of course, the cost of removing the receipts from a particular coin telephone can be reduced by reducing the collection frequency. But reducing collection frequency beyond a certain point results in lost receipts, since the telephone cannot be operated once the collection box is full. Furthermore, since the rate at which a given telephone becomes filled with coins can vary significantly from time to time, a time duration that is adequate between visits at one time may be too long at another time and may result in an unnecessary visit at a third time.
As a result, the use of auditors at coin-telephone locations has been proposed. Coin-telephone auditors keep track of the amount of money collected and send the collection information to a central location at which collections are scheduled. In some systems, equipment at a central location polls the remote auditors to determine whether the associated telephones need to be emptied. In other systems, the local coin-telephone auditor sends the information whenever a user places a call on the coin telephone.
There are many types of auditors, but all of them suffer from one or more of several drawbacks. Some, for instance, require extra communication lines to carry the information. Others increase the traffic on the normal telephone lines excessively because of the frequent polling needed to ensure that collections are kept current. Also, many auditors require power connections or substantial modifications of the coin telephone or of the central-office equipment so that the information can be recorded when a user makes a call.
It is accordingly an object of the present invention to provide the auditing function with local equipment that requires minimal modification of the coin telephone itself, requires no modification of central-office equipment, and can be operated by telephone-network power alone.